Maximum Combinations

public class AllCombinations

{   private static void allIndexes(int a[], int index)

    {   a[index]++;

        for(int i=index+1; i<a.length; i++) a[i]=0;

        if(a[index]==a.length)

        {   a[index]--;

            if(index>0) allIndexes(a, index-1);

        }

    }

    private static boolean unique(int a[])

    {   for(int i=0; i<a.length-1; i++)

        {   for(int j=i+1; j<a.length; j++)

            {   if(a[i]==a[j]) return false;

            }

        }

        return true;

    }

                       

    public static void main(String args[])

    {   String s="BAT";

        int a[]=new int[s.length()];       

        for(int n=0; n<(int)Math.pow(a.length, a.length); n++)

        {   if(unique(a))

            {   for(int i=0; i<a.length; i++) System.out.print(s.charAt(a[i]));

                System.out.println();       

            }

            allIndexes(a, a.length-1);

        }               

    }//main

   

   

}//class